新型超宽带雷达发射机技术

对阶跃恢复二极管( SRD)在方波激励下的电特性作了较为深入的研究，根据SRD的特性将其等效为可变结电容和普通pn二极管的并联，可变结电容的模型以SRD的外特性实测数据为依据，用三段线性结电容来拟合SRD的结电容。提出了一种基于SRD、肖特基二极管和微带短路线产生超宽带( UWB)、单周期窄脉冲的方法，对窄脉冲产生电路的工作原理进行了理论分析和软件仿真，设计并实现了新型超宽带雷达发射机，经测试单周期窄脉冲的脉宽为400 ps，峰峰值为15 V，测试结果与分析仿真结果基本吻合，从而验证了SRD模型和对窄脉冲产生电路分析的正确性。     

基于CPLD的超宽带引信脉冲发生器设计

脉冲发生器是超宽带引信系统的关键电路，必须考虑设计合理的脉冲发生器。提出了基于CPLD的超宽带无线电引信的系统原理，并对其工作过程进行了说明；设计了亚纳秒级脉冲发生器，介绍了该电路的工作原理并对其进行了仿真．根据仿真结果分析了输出波形的特征，验证了超宽带引信的优良特性。同时，该脉冲发生器电路结构简单，容易实现且性能完全能达到实用要求。     

基于射频三极管的超宽带引信脉冲源

针对当前基于阶跃恢复二极管的超宽带脉冲源成本高、电路复杂、工作电压高的不足,提出了基于射频三极管的超宽带引信脉冲源电路.该电路是以射频三极管为核心,利用射频三极管的低价和低压雪崩特性,结合电感器件磁场能存储与释放效应构建一种成本较低、电路简单、工作电压低的脉冲源.借助ADS仿真软件对电路进行了仿真测试,实际电路可以输出脉冲峰谷宽度为700 ps,幅度达8.608 V的亚纳秒的双极窄脉冲信号.测试结果表明该脉冲源能满足超宽带引信的需要.     

超宽带引信取样脉冲宽度与相关接收输出信号幅度关系研究

超宽带无线电引信接收机基于相关接收原理获取预设炸高处的目标回波信号,回波信号与经过延迟的取样脉冲信号进行相关运算得到引信接收机输出信号。优化取样脉冲宽度可以提高超宽带引信探测灵敏度。根据超宽带引信相关接收原理,建立超宽带引信相关接收数学模型,分析取样脉冲宽度与相关接收函数幅值的关系。发射脉冲宽度分别为50 ps、100 ps、200 ps时对引信相关接收输出信号进行仿真,仿真结果表明取样脉冲宽度与发射脉冲宽度相等时引信相关接收输出信号幅度最大;通过实验结果验证了该理论模型的正确性。研究结果适用于超宽带引信接收机优化设计。     

引信电路的可靠性及预计

针对引信电路的特点，提出了电路失效与一般产品的差别和评价的重点及设计可靠性的概念。给出了设计可靠性的建模方法和用数字仿真评估设计可靠性的模型方法和仿真过程并给出了一个典型电路的仿真实例。     

一种新型雷达引信系统及其抗干扰性能分析

介绍了一种新型超宽带线性调频雷达引信系统,对其工作原理进行分析,给出基于超宽带线性调频信号的目标回波模型及其模糊函数的Matlab仿真结果。最后,对其抗干扰性能进行分析和探讨,结果表明,这种引信系统具有较强的抗干扰能力。     

引信电路的可靠性及预计

针对引信电路的特点，提出了电路失效的一般产品的差别和评价的重点及设计可靠性的概念。给出了设计可靠性的建模方法和用数字仿真评估设计可靠性的模型方法和仿真过程并给出了一个典型电路的仿真实便。     

超宽带引信脉冲发生器设计

针对基于射频三极管、阶跃恢复二极管的脉冲源产生的超宽带信号幅度较小、作用距离短,而基于雪崩三级管的脉冲源需要体积较大的电压源等问题,设计了一种基于雪崩三极管的小型化超宽带脉冲源来产生大幅值的超宽带信号,该电路用逆变电路将干电池电压升至所需电压,加至雪崩管集电极产生雪崩效应,输出纳秒级窄脉冲。用示波器测试实际电路产生信号,脉冲宽度约为500ps,幅值约10V。该电路有效地提高了信号幅值,进而提升引信作用距离,且占用空间很小。     

对空冲激引信技术

介绍了冲激引信的基本原理和技术特点,给出了一种基于超宽带雷达动目标检测原理和收发分开的技术方案,指出了冲激引信的三大关键技术：与防空导弹弹体共形的超宽带天线技术、基于阶跃恢复二极管的超窄脉冲产生器技术和基于超宽带雷达动目标检测原理的匹配接收机技术,提出了关键技术解决途径,最后给出了原理样机的试验验证结果。     

阶跃恢复二极管参数对窄脉冲波形的影响研究

阶跃恢复二极管是超宽带引信产生窄脉冲信号的核心器件,阶跃恢复二极管参数影响窄脉冲信号的幅度和宽度。依据半导体器件理论和阶跃恢复二极管不同的工作状态,建立阶跃恢复二极管模型,分析阶跃恢复二极管参数对二极管正偏导纳和反偏势垒电容的影响。根据窄脉冲产生等效电路,采用电路暂态分析方法求解窄脉冲幅度和窄脉冲宽度,仿真研究阶跃恢复二极管少数载流子寿命、反向饱和电流、零偏结电容和掺杂分布系数与窄脉冲幅度和窄脉冲宽度关系。仿真结果表明,改变阶跃恢复二极管参数可以调节窄脉冲幅度和窄脉冲宽度,通过产生的窄脉冲与仿真结果对比分析,验证了仿真结果的正确性。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Design and Analysis of Test Schemes of Static Postponing Time on Shrapnels Used to Riot Control

The test scheme of static postponing time given in our actual national military test standard on shrapnels used to control riot is a nine-point test scheme on the combined action of three kinds of temperatures and three kinds of pressures,the consumed ammunitions are more excessive. Statistic analysis and tentative checkout about a lot of test data are done,feasibility gists are put forward for optimizing of the test design scheme. The optimizing design and data analysis of test scheme of the item are done by managing uniformity design theory, two scientific and reasonable six-point test schemes are confirmed. The feasibility and reliability of the optimizing design schemes put forward above are proved ulteriorly by test validating. The gained schemes not only have good design uniformity and little ammunition wastage and meet the test demand, but also have better forecast ability for the result data of other points using the mathematic models from the actual test points.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

Design of Non-fragile Satisfactory Estimator for Linear Continuous Perturbed Stochastic Systems

The design problem of non-fragile estimator is addressed for a class of perturbed linear continuous systems. The perturbations occur on the plant and estimator parameters. The estimator designed should force the error system to achieve the desired decay rate and force the steady error variance less than the specified upper bound irrdevancy of the admissible plant perturbations and estimator perturbations. Consistency problem of the decay rate with the variance upper bound is first considered via linear matrix inequality （LMI） approach. The solution of the estimator parameter under specifications to be consistent is then discussed. The consistency condition of specifications and estimator parameter solution are transformed to feasible or minimum problems subject to a set of LMI respectively. The method is illustrated by a numerical example.     

An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

The improved scene-based adaptive nonuniformity correction （NUC） algorithms using a neural network （NNT） approach for infrared image sequences are presented and analyzed. The retlna-like neural networks using steepest descent model was the first proposed infrared focal plane arrays （IRFPA） nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij （ n ） is proposed as an alternative value of desired network output of neuron Xij （ n ）, denoted as Tij （ n ）, which is the local spatial average of Xij （ n ） in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences （several hundred frames） subjected to the dense impulse noises with a number of dead or saturated pixels.     

Piecewise Filter of Infrared Image Based on Moment Theory

The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge, To solve this problem, a piecewise moment filter （PMF） is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge. At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.     

Bistatic Sonar Localization Based on Best Linear Unbiased Estimation

A best linear unbiased estimation （BLUE） algorithm for bistatic sonar localization is proposed. The Cramer-Rao bound for bistatic Sonar and the geometrical dilution of precision （GDOP） in different conditions are given. The simulation results show that the location accuracy of BLUE algorithm is higher than the weighted least square method.